title: Central endogenous angiotensin-(1-7) protects against aldosterone/NaCl-induced hypertension in female rats.
abstract: In comparison to male rodents, females are protected against angiotensin (ANG) II- and aldosterone (Aldo)-induced hypertension. However, the mechanisms underlying this protective effect are not well understood. ANG-(1-7) is formed from ANG II by angiotensin-converting enzyme 2 (ACE2) and has an antihypertensive effect in the central nervous system (CNS). The present study tested the hypothesis that central ANG-(1-7) plays an important protective role in attenuating the development of Aldo/NaCl-hypertension in female rats. Systemic infusion of Aldo into intact female rats with 1% NaCl as their sole drinking fluid resulted in a slight increase in blood pressure (BP). Intracerebroventricular (icv) infusion of A-779, an ANG-(1-7) receptor (Mas-R) antagonist, significantly augmented the pressor effects of Aldo/NaCl. In contrast, systemic Aldo/NaCl induced a significant increase in BP in ovariectomized (OVX) female rats, and central infusion of ANG-(1-7) significantly attenuated this Aldo/NaCl pressor effect. The inhibitory effect of ANG-(1-7) on the Aldo/NaCl pressor effect was abolished by concurrent infusion of A-779. RT-PCR analyses showed that there was a corresponding change in mRNA expression of several renin-angiotensin system components, estrogen receptors and an NADPH oxidase subunit in the lamina terminalis. Taken together these results suggest that female sex hormones regulate an antihypertensive axis of the brain renin-angiotensin system involving ACE2/ANG-(1-7)/Mas-R that plays an important counterregulatory role in protecting against the development of Aldo/NaCl-induced hypertension.
authors.affiliation: Department of Psychology, University of Iowa, Iowa City, Iowa;
authors.forename: Baojian
authors.initials: B
authors.lastname: Xue
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Zhang
authors.forename: Ralph F
authors.initials: RF
authors.lastname: Johnson
authors.forename: Fang
authors.initials: F
authors.lastname: Guo
authors.forename: Meredith
authors.initials: M
authors.lastname: Hay
authors.forename: Alan Kim
authors.initials: AK
authors.lastname: Johnson
mesh_terms: D000450:Aldosterone / Q000009:adverse effects* / Q000494:pharmacology; D000803:Angiotensin I / Q000378:metabolism*; D000085962:Angiotensin-Converting Enzyme 2; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D006973:Hypertension / Q000139:chemically induced* / Q000378:metabolism / Q000517:prevention & control*; D019255:NADPH Oxidases / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000502:physiology; D012737:Sex Factors; D012965:Sodium Chloride / Q000009:adverse effects* / Q000494:pharmacology
chemical_list: D010446:Peptide Fragments; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D012965:Sodium Chloride; D000450:Aldosterone; D000803:Angiotensin I; D019255:NADPH Oxidases; D007703:Peptidyl-Dipeptidase A; C000705329:Ace2 protein, rat; D000085962:Angiotensin-Converting Enzyme 2; C118790:angiotensin I (1-7)
keywords: aldosterone; angiotensin-(1–7); blood pressure; central nervous system